Yes, you are required to provide your passport or national ID details to Ryanair, but usually only during the online check-in process, not necessarily at the time of booking. For flights within the Schengen Area, you still need to provide these details for manifest requirements. For international/non-Schengen flights (e.g., UK to Spain), this information is mandatory for Advanced Passenger Information (API). In 2026, Ryanair has increasingly utilized their mobile app for "document verification," where you can scan your passport chip using NFC to speed up the process. If you fail to provide these details and check in online (usually 24 hours to 2 hours before departure), you will be forced to pay a heavy "Airport Check-in Fee" (currently around £/€55), making it vital to complete this step digitally.